A wireless local area network (WLAN) client device may store in its memory one or more profiles of wireless local area networks. A profile may include, for example, the service set identity (SSID) of the network, WLAN configuration parameters, security credentials, and Internet Protocol (IP) network parameters. The SSID is also known as the network name. The profiles may be assigned priorities, for example, by a user that has purchased the client device, a carrier who controls the sale of the client device, or an administrator of an enterprise that has purchased the client device.
Scanning is the process of identifying existing networks. A client device having two or more profiles may scan for WLANs matching the profiles in sequence, and if no successful connection is achieved then the client device may go into a sleep state for a sleep interval (e.g., a few seconds) before trying to scan the profiles again. This may be applicable only to profiles of WLANs having suppressed SSIDs.
While a device is not in coverage and is scanning for WLANs, the average amount of charge drawn from its battery may be related to the ratio between the time spent in the sleep state and the time spent scanning. For a device with N profiles, an exemplary sequence for scanning/sleeping may be as follows: P1P2 . . . PN Sleep1 P1P2 . . . PN Sleep2 P1P2 . . . PN Sleep3 P1P2 . . . PN Sleep4 P1P2 . . . PN where Sleep1, Sleep2, . . . are sleep intervals between profile scanning intervals, and the duration of sleep intervals may be increased (that is, Sleep1<Sleep2<Sleep3< . . . ) until it reaches an upper limit. The more profiles the device is scanning for, the lower the ratio between the time spent in the sleep state and the time spent scanning. This may have an adverse effect on the battery life of the device.
It will be appreciated that for simplicity and clarity of illustration, elements shown in the figures have not necessarily been drawn to scale. For example, the dimensions of some of the elements may be exaggerated relative to other elements for clarity.